1. Field of the Invention
The present invention relates to a ceramic superconducting member, and more particularly, it relates to a ceramic superconducting member which is applied to a cable, a device or the like employing a ceramic superconductive material.
2. Description of the Prior Art
It has recently been found with great interest that certain ceramic superconductive materials superconduct at high critical temperatures. Such a ceramic superconductive material is generally manufactured for experimental purposes by compression-molding a raw material through press working and thereafter sintering the same, to employ the same in the form of a ceramic pellet.
It has been provided that, for example, a superconductive material of Y-Ba-Cu-O has a critical temperature of at least 90 K.
In order to put such a ceramic superconductive material into practice, however, it is necessary to cool the same to a temperature lower than the normal temperature. Thus, a cooling medium such as liquid nitrogen is employed. For example, a device formed by a member of a ceramic superconductive material is used under presence of a cooling medium in order to effectuate its superconductivity, while the member is placed under the normal temperature when the same is not used. Thus, the member is repeatedly subjected to a number of heat cycles in environment having temperature difference for superconduction and non-superconduction under a low temperature and the normal temperature. Therefore, water vapor contained in the atmospheric air may be condensed by such temperature difference, to bedew the surface of the member with water droplets. It is assumed that, even if such a ceramic superconductive material is discovered which can superconduct at normal temperature in the future, the surface thereof may be bedewed with water droplets by water vapor contained in the atmospheric air, depending on environment.